Can anyone tell me where the A/C low pressure switch located and what wires to jump on it to engage the internal clutch in the compressor on my 2012 Mercedes Gl550. I have changed the compressor, expansion valve, dryer and vacuum tbe system down. Compressor is not engaging to charge system. Its not pumling. Please help.
2012 Mercedes Gl550 a/c low pressures switch location
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There is no low pressure switch. Refrigerant pressure and temperature are read by digital sensor.
What can I do to get this system to charge. Also how can I tell if the compressor clutch is turning
Also Do you know where I can purchase a repair shop manual for my Mercedes GL550?
There is no officially published manual.
Rubber side up 😤
So my son decided to test acceleration vs. handling on a horseshoe onramp with our 07 GL450. Needless to say, with limited experience the vehicle ended up on the driver's side. He is ok, which is the main thing and I would rather it happen in a Mercedes than anything else for obvious safety...
www.benzworld.org
You connect battery charger, scanner and read codes first. From all control modules that is.
If there are faults for evaporator temp sensor or refrigerant pressure/temp compressor will not get activated. Baseball bat or not.
Thank you for the information, I'll check for codes.
Compressor is connected to controller N22, connector B, pin 26. It is 12V PWM signal. Around 700mA with 100% demand.
Is controller n22 the A/C control in the middle of my console that control the power on, temperature for both side and vents? Sorry, I'm not knowledgeable on Mercedes.
Yes. it is.
Thank you so much, I'll check it. Also thank you for the attachments from your earlier reply.
The problem is I'm only getting 0.5 volts at the compressor through the blue/green wire when the ac is on at all time. Please read the below things.
1. After replacing the ac compressor the new compressor will not pump just like the old compressor. A shop lie to me and said the old compressor was bad. They wanted $2400 to change out the intire system.
2. I changed out the compressor, dryer, expansion valve, new o rings and pull a vacuum.
3. I disconnected the plug to the compressor and jumped started the compressor with a 15amp fuse in a wire and my battery pack, using a different power source.
4. The compressor came on and I was able to charge the system completely.
5. I did a continuity on the blue/green wire at the compressor and found it to be good.
Any other suggestions
The problem is I'm only getting 0.5 volts at the compressor through the blue/green wire when the ac is on at all time. Please read the below things.
1. After replacing the ac compressor the new compressor will not pump just like the old compressor. A shop lie to me and said the old compressor was bad. They wanted $2400 to change out the intire system.
2. I changed out the compressor, dryer, expansion valve, new o rings and pull a vacuum.
3. I disconnected the plug to the compressor and jumped started the compressor with a 15amp fuse in a wire and my battery pack, using a different power source.
4. The compressor came on and I was able to charge the system completely.
5. I did a continuity on the blue/green wire at the compressor and found it to be good.
Any other suggestions
Most of modern circuits are protected by electronic "fuses". Power gets sent to component. If current draw is outside of spec output is shut down.
Disconnecting compressor and measuring output from N22 falls in that area. All measurements need to be done with components connected using backprobe method.
You need to limit current to 700mA or you will smoke compressor solenoid.
If you're getting a P9006 error after putting in a new compressor, you probably need to add a diode between the blue green wire and ground Details here: Fix: P9006 short circuit error when replacing AC compressor - MBWorld.org Forums and here: Ac problems code 9006 - MBWorld.org Forums
I've had zero problems with my compressor engaging after adding the diode.
I've had zero problems with my compressor engaging after adding the diode.
Thank you for sharing the information about the diode in the compressor, that fixed my problem, I thank you so much for sharing the information. It was well worth joining the BenzWorld.
Thank you for all your replies, it was very helpful and help me fix my wife GL550.
So, what fixed it?
I put in the diode, which took care of the back feed causing the code.
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